Society =/= Every possible opinion.
Society is the majority
And as a society, we do not want to die out by not having kids. I mean, really.
Of course some don't want to have 'em. That's fine. Your call.
But yeah, I'm sorry, but I won't avoid having a kid because I think they could go crazy. I'll avoid it for a legitimate reason that's realistic enough, like I couldn't handle taking care of a kid. Something that's not a severe future prediction that can't be backed up whatsoever with facts.
Let's go with facts; Anybody could become anybody after born. It's our job as parents to teach them to be productive members of society, as well as good people as is. Not everybody can handle this, of course. That's fine.
But we don't get anywhere by never having children. That doesn't solve a single problem. Most of those "problems" that you're derailing with can be solved with good teaching, better parenting, and therapy. It doesn't help to basically "kill" any hope of that happening. We didn't get better at life via never having more children. We're grown as people by having more and learning new things. That's how it's always worked.
In fact, it was way worse back then, and it has gotten better, but only because we didn't basically make the race extinct. Your solution, frankly, does not solve anything. It's essentially a slow and non-painful way to murder the entire race, by never continuing it.